This is a substitute of application Ser. No. 365,811 filed May 31, 1973, now abandoned.
The present invention relates to aneroid pressure gauges of the type used in a sphygmomanometer for clinical blood pressure determinations and to means for easily forming a permanent record of pulse readings.
The measurement of blood pressure is normally obtained by the use of sphygmomanometer generally comprising an inflatable cuff or sleeve for applying pressure to an artery. A mercury-gravity manometer or an aneroid manometer inflating bulb is used to generate air pressure in the cuff including a valve for bleeding off air pressure at any desired rate. Additionally, a stethoscope is used to hear the Korotkov sounds. Blood pressure determination, with such equipment, is made by increasing air pressure in the cuff until arterial flow is completely stopped. The bleed off valve is then opened to permit deflation of the cuff until blood begins to flow again and the onset of the Korotkov sounds is heard in the stethoscope. The pressure at which this event occurs is the systolic pressure and its magnitude is noted. As air pressure in the cuff is further reduced, blood flow is impeded by the cuff pressure proportionally less during each heart cycle until the blood flow becomes continuous and the Korotkov sounds disappear. This pressure is the diastolic pressure and is noted. While obtaining blood pressure readings in the foregoing manner it is necessary to focus attention simultaneously on the threshold or disappearance of sound in the stethoscope and on the moving display of the declining pressure function by the mercury-gravity manometer or pointer of an aneroid manometer. When once observed it is necessary to remember the pressures at which the Korotkov sounds appear and disappear until the measurement has been completed and they can be written. These observations and memory functions to obtain accurate blood pressure readings must be performed by trained personnel, and even then sometimes requires repeated measurements to obtain accurate readings.
The principle feature of this invention resides in its simplicity of construction and simplicity of operation wherein personnel with little or no training may easily learn to operate the syphgmograph and obtain a permanent record of blood pressure reading to be added to the patient's record.